Phthalocyanines cationic

The porphyrins constitute another class of nitrogen donor ligands which favor Ag(II) over Ag(I). Their macrocychc stmeture provides strong in-plane ligand fields, which facilitate oxidation of the metal. Phthalocyanine complexes of Ag(II) are very stable and can be oxidized electrochemically to Ag(III) further oxidation gives a Ag(III) phthalocyanine cation radical. The oxidation of Ag(I) complexes of sulfur macrocycles also leads reversibly to Ag(II) complexes. ... 

Given stringent requirements for effective sensitizers and the desire to use wavelengths further to the red for therapeutic appHcations, definition of newer sensitizers has been a principal area of research since about 1987. Expanded theoretical and experimental understanding of photophysics has been a key element in identifying new classes of potential sensitizers (93—98). Research has focused on cationic derivatives of Nile Blue (93), metaHo-phthalocyanines (94), naphthalocyanines (95), chlorin-type compounds (96), expanded ring porphyrinoids (97), as well as porphyrins other than hematoporphyrin and its derivatives (98). This work has also been reviewed (10,91). Instmmentation for photodynamic therapy has been reviewed (99). 

Photooxidafions are also iudustriaHy significant. A widely used treatment for removal of thiols from petroleum distillates is air iu the presence of sulfonated phthalocyanines (cobalt or vanadium complexes). Studies of this photoreaction (53) with the analogous ziuc phthalocyanine show a facile photooxidation of thiols, and the rate is enhanced further by cationic surfactants. For the perfume iudustry, rose oxide is produced iu low toimage quantifies by singlet oxygen oxidation of citroneUol (54). Rose bengal is the photosensitizer. 

Thallium phthalocyanine (PcT12) can be obtained by heating phthalonitrile with an inter-metallic alloy of indium and thallium in an evacuated glass ampule.145 The structure of this compound is unique among metal phthalocyanines as the two thallium cations occupy two opposite corners of an octahedron, which is formed by the thallium cations and the four iso-indolinc nitrogen atoms facing the center of the macrocycle.147 Another unusual type of phthalocyanine can be prepared by heating phthalonitrile with thallium metal.148 It was identified as a bicyclic thallium(III) phthalocyanine (Pc3/2T1).14S... 

Polymeric phthalocyanines 3 are available from 1,2,4,5-tetracyanoben ne 2 by deposition from the vapor phase on hot substrate surfaces, or by thermal curing of its tetramer, octacyanophthalocyanine 4 in the presence of metal cations (Scheme 2... 

Fig. 13 List of some recent cationic phosphorus phthalocyanines of type 60...

The penetration of ions from the subphase into the shell of spread particles is a general phenomenon and can be used to modify and functionalize the particle surface. For example, metal ions, such as Ba and Fe, or cationic polyelectrolytes, such as the polycation of polyallylamine, can be adsorbed at anionic particles, while anionic water-soluble dyes, such as phthalocyanine tetrasulfonic acid and 1.4-diketo-3.6-diphenylpyrrolo[3.4-c]pyrrole-4, 4 -disulfonic acid (DPPS) [157], can be adsorbed at cationic particles. However, since only a monolayer of the dye is adsorbed, a deep coloration of the particles is not obtained unless a dye with very high absorption coefficient is used [156],... 

Pillared clays (MELS) are aLso covered in this review. MELS have three-dimensional network structure like zeolites, and, unlike clays, which have two-dimensional layered structures, pillared cationic and anionic clays have been studied. Phthalocyanins intercalated in anionic clays have given interesting results for wastewater purification (Vaccari, 1998). 

The redox potentials of zinc-substituted phthalocyanines are shown to be linearly dependent on the total Hammett substituent constant.837 In 1987, Stillman and co-workers used the absorption and magnetic circular dichroism spectra of the zinc phthalocyanine and its 7r-cation-radical species to assign the observed bands on the basis of theoretical calculations. The neutral and oxidized zinc phthalocyanine complexes with cyanide, imidazole, and pyridine were used with the key factor in these studies the stability of the 7r-cation-radical species.838 The structure of zinc chloro(phthalocyaninato) has been determined and conductivity investigated.839... 

The photophysical properties of magnesium(II) tetra-(i-butyl)phthalocyanine (27) have been studied in solution, in micelles and in liposomes cation radical formation (CBr4 as electron acceptor) has been detected with UV excitation, or by a two-photon excitation using a pulsed laser in the therapeutic window at 670 nm.118 The Mg11 complex of octa(tri-z -propylsilylethy-nyl)tetra[6,7]quinoxalinoporphyrazine (28) has been prepared as a potential PDT sensitizer. The synthesis is shown in Figure 8. Compound (28) has Amax 770 nm (e = 512,000 M-1 cm-1), d>f = 0.46 and d>A = 0.19 (all in THF, under air).119... 

Ring systems intermediate between phthalocyanines and naphthalocyanines are known 263,264 (51) is such a compound. They are most simply called benzonaphthoporphyrazines, and various zinc(II) complexes with cationic (A--m e t hy 1 pyridini um-3-oxy) substituents have Amax in the range 680-750 nm in solution or in Cremophor micelles, and show promise in bioassays in vivo.264... 

The silicon(IV) phthalocyanine (12) is also effective in the photoinactivation of the parasite Plasmodium falciparum384 and various enveloped viruses in red blood cell concentrates.385-387 Other silicon (and aluminum) phthalocyanines have been evaluated for the photoinactivation of viruses cationic derivatives appear to be most effective.388... 

In abroad sense, the model developed for the cobaloxime(II)-catalyzed reactions seems to be valid also for the autoxidation of the alkyl mercaptan to disulfides in the presence of cobalt(II) phthalocyanine tetra-sodium sulfonate in reverse micelles (142). It was assumed that the rate-determining electron transfer within the catalyst-substrate-dioxygen complex leads to the formation of the final products via the RS and O - radicals. The yield of the disulfide product was higher in water-oil microemulsions prepared from a cationic surfactant than in the presence of an anionic surfactant. This difference is probably due to the stabilization of the monomeric form of the catalyst in the former environment. 

Electrochemistry. The redox processes for porphyrazines 21, 25, 28, 29, the heteroleptic Zr (pz/porphyrin) 30 and 31 have been measured by cyclic voltammetry and the formal potentials are given in Table VII. The potentials are compared to the available data for the analogous porphyrin and pc complexes. In general, the electrochemical behavior of the pz sandwiches more closely mirror that observed for the phthalocyanines than the porphyrins. In particular, all of the porphyrazines have at least one ring-based oxidation, attributable to the formation of the bis Jt-radical cation for Lu(III) sandwiches and the formation of the 7T-radical cation for the Zr(IV) and Ce(IV) sandwiches. Additionally, all of the porphyrazines exhibit at least one ring-based reduction. 

Knowledge of the most important types of copper phthalocyanine pigments is useful for the understanding of the processes concepts underlying pigment manufacture. Heading the list are the a- and [i-modil i cations of unsubstituted Copper Phthalocyanine Blue (Sec. 3.1.2.3). The a-modification exhibits an unstabilized and a stabilized form as to change of crystal modification. 

Minnock A, Vernon DI, Schofield J, Griffiths J, Parish JH, Brown SB (1996) Photoinactivation of bacteria. Use of a cationic water-soluble zinc phthalocyanine to photoinactivate both gramnegative and gram-positive bacteria. J. Photochem. Photobiol. B 32 159-164. 

Where MPe represents the phthalocyanine in an excited triplet state. The CBr3 species is expected to dimerize rapidly following the reaction. The quantum yields of the resulting phthalocyanine n cation radical are shown in Table H. The EPR spectra obtained at 79 K for the ZnPc and RuPc n C U ion radicals give isotropic g values (Table II), which are very close to the free electron value of 2.0023 and are characteristic of the n caJtion radic ds of phthalocyanines (10,15). 

The template synthesis method involves the diffusion of ligand precursors into the pores of a zeolite where they can assemble around an intrazeolite metal ion that acts as a template. This approach was first used in 1977 for the intrazeoHte synthesis of Cu, Co and Ni phthalocyanines by the condensation of four molecules of dicyanobenzene around the metal cation within the cages of NaY [132, 174]. 

The protons released are presumably available to compensate for the loss of the charge balancing cations within the zeolite. In conventional syntheses, the phtha-lonitrile condensation normally requires the nucleophilic attack of a strong base on the phthalonitrile cyano group [176, 177]. This function is presumably accommodated by the Si-O-Al (cation) basic sites within the ion-exchanged faujasite zeolites [178, 179]. The importance of this role is perhaps emphasized by the widespread use of alkali metal exchanged faujasites, particularly the more basic NaX materials of higher aluminium content [180, 181] as hosts for encapsulated phthalocyanine complexes. 

Oxygenic photosynthetic organisms, [2Fe-2S] ferredoxins, 38 224-233 Oxygenyl ion, preparation of, 9 229 Oxyhalides, of berkelium, 28 49, 51-53 Oxyhalogeno cations, 9 276-279 Oxyhemerythrin, 40 373-374, 45 84 XAS, 36 325 Oxyhemocyanin, 40 363 m-peroxo dinuclear copper complexes as models for, 39 41-52 physicochemical properties, 39 47-48 Oxyhemocyanins, XAS, 36 326-327 Oxyhemoglobin, 21 135 Oxyiodonium cations, 9 277 Oxymanganese phthalocyanine, strucmre of, 7 31-35... 

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